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THE OHIO STATE UNIVERSITY BULLETIN 
Vol. l6 November, 1911 No. 9 


A STUDY OF THE RATTLER TEST FOR PAVING BRICK 




BY 


M. W. BLAIR and EDWARD ORTON, Jr. 





BULLETIN No. 3 
COLLEGE OF ENGINEERING 


> j 

• • j 


PUBLISHED BY THE UNIVERSITY 

COLUMBUS, OHIO 


Entered as Second Class Matter, November 17th, 1905, at the Post Office at Columbus, Ohio, 

under Act of Congress, July 16, 1894. 


/<! - Vb '2~H % 


























Authorized Reprint from the Copyrighted 
Proceedings of the American Society for Testing Materials, 

Philadelphia, Penna. 

Volume XI, 1911. 

A STUDY OF THE RATTLER TEST FOR PAVING 

BRICK. 


By M. W. Blair and Edward Orton, Jr. 

Introduction. 

The rattler test for determining the relative resistance of 
paving bricks to impact and abrasion has been in use since the 
late eighties, when the paving of streets with brick began to make 
headway in America. The simplicity and competitive features of 
this mode of testing has from the first strongly appealed to all 
concerned. The early mode of testing was to put two or more 
bricks of as many different samples as were in competition, into a 
rattler of appropriate size, fill the bulk of the residual space with 
scrap iron of any sort available, and rotate the barrel at any 
convenient speed for from one to six hours, and determine the 
losses of each variety. Of course, under such conditions, there 
was no likelihood of the original operator being able to check his 
results, and no possibility of rattler tests made in different places 
being compared at all. 

The first efforts at standardization of the test began in 1895 
and resulted in 1901 in the rather wide acceptance of a method 
known as the N. B. M. A. test. For a much fuller historical 
statement of the beginnings of the rattler test, see the chapter by 
A. N. Talbot, Bulletin 9, Geological Survey of Illinois. 

This standard has been the criterion upon which hundreds of 
millions of paving bricks have been judged. It has done great 
good, by reducing to comparative order a condition which had been 
chaotic. It was recognized by the committee of engineers and 
manufacturers who framed the N. B. M. A. specifications, that 
these were not as full and well defined as was desirable, but it was 
considered unwise and premature to attempt too rigid and precise 
definition for fear of stopping the use of the test entirely. Some 
of the points left open or poorly defined in these specifications have 
since been shown to be capable of exerting a very appreciable 
disturbing effect. 

Criticisms of the rattler test have, therefore, been occurring at 
all times since its adoption, and while not able to bring about the 

( 77 6 ) 




Blair and Orton on the Rattler Test. 777 

overthrow of the test, they have been bringing about in the minds 
of all concerned a steadily increasing desire for more exact and 
better defined specifications. The National Paving Brick Manu¬ 
facturers Association in 1909 decided to undertake an investigation, 
with a view to supplying this need. They employed Mr. Marion 
W. Blair to conduct the investigation for them. Some time after 
this work was initiated, but before actual testing began, Professor 
Edward Orton, Jr., came forward with a proposition to cooperate 
in the proposed investigation by making duplicate studies at his 
own expense, and by exchange of data with Mr. Blair, to more 
fully test out the value of all proposed changes in specifications. 
This offer was accepted by the Association and joint work was 
begun in April, 1910, and continued into June of 1911. This 
paper sets forth the results of this study, in part, together with 
recommendations for a proposed standard method of making the 
rattler test. 

Plan of the Investigation. 

The plan decided upon was as follows: 

First: To equip both operators with identical machines, made 
from the same patterns, in the same foundry. 

Second: To equip both operators with a large supply of 
paving bricks from ten different manufacturing plants, these 
samples to be selected so as to secure a variety in type of product 
but as much uniformity within each sample as the nature of the 
product permits. 

Third: To make a series of duplicate tests under conditions to 
be carefully prescribed in advance, with a view to determining what 
degree of concordance could be obtained with the standard charge 
of cubic cast-iron shot as prescribed by the old N. B. M. A. tests. 

Fourth: To make similar duplicate series using spherical 
cast-iron shot, and also with no shot, and following in other 
respects the same procedure before described, with a view to 
reducing the cost of making the test without decreasing its efficiency. 

Beside these comparative studies of the rattler test,, there 
were proposed and carried out certain other studies, such as the 
difference in quality of bricks representing the different parts of 
the kiln, the possible use of the absorption test as a mode of grading 
material for the rattler test, etc., which are not germane to the 


778 Blair and Orton on the Rattler Test. 

subject here under discussion, and to which no further attention 
will be drawn in this paper. These data will be presented in 
another paper elsewhere.* 

In carrying out the above outline, a carefully prepared set 
of rules was agreed upon. These rules covered storage, mode of 
selection of samples, system of designating tests on each sample, 
number of tests of each kind to be made, mode of conducting the 
absorption test, selection of charges of bricks from those graded by 
absorption, condition of rattler (especially the staves), dimensions 
and quality of shot, mode of rejection of worn-out shot, mode of 
starting with charges of new shot, quality of iron in the shot, speed 
and duration of test, stopping and starting, weighing charges, 
computation of results, and many other minutiae. The same 
blank forms for recording all data were also used by both operators. 

If all of the above rules had been rigorously observed through¬ 
out by both operators, an earlier concurrence would undoubtedly 
have been obtained. From a lack of appreciation of the impor¬ 
tance of exact observance, some differences of procedure did creep in 
from the beginning, and the most valuable knowledge obtained in 
the whole study has come from “running down” the discrepancies 
in the results thus produced, for it has demonstrated the importance 
of factors not heretofore suspected, and shown how rigid the condi¬ 
tions of the test must be to secure a proper concordance between 
different operators. 

Series F. 

The first ten letters of the alphabet were agreed upon to 
represent the ten different brands of bricks to be studied. The 
first sample to arrive was that designated by the letter F. The 
quantity was 2,100 bricks, which was equally divided between the 
two laboratories. 

In equipping the two laboratories with cast-iron shot, it was 
provided that one common lot of each kind of shot, both cubic 
and spherical, was to be procured and divided. This was done, 
but with some delay. Prior to the arrival of the shot at Blair’s 
laboratory, he had procured a supply of both cubic and spherical 
shot from the Over Foundry in Indianapolis, and started his tests. 

* Orton—“ Some Observations on the Qualities of Paving Brick.” Transactions, 
American Ceramic Society, Vol. XIII, p. 792. 



Blair and Orton on the Rattler Test. 


779 


Orton, in procuring the shot for distribution, had purchased 
from two different Columbus foundries. In all cases, both in 
Indianapolis and Columbus, the same specifications as to hardness 
of shot, quality of iron, etc., were used and the shot received was 
supposed by both operators to meet the requirements with sufficient 
exactness. 

Thus, when the testing of Series F began, there were three 
different lots of shot in use, viz.:—spherical shot made by the 
H. Loudenslager Foundry Company, of Columbus, used by Orton; 
cubic shot made by O’Brien Brothers, of Columbus, used by 
Orton; cubic and spherical shot made by the Over Foundry, of 
Indianapolis, used by Blair. None of these inequalities were 
recognized as important, at the beginning. 

A slight further inequality in conditions was brought about by 
Blair using his machines for some preliminary testing on materials 
for Series H and K, which had come into his possession early, but 
which had not reached Orton’s laboratory. Thus, when Series F 
was begun, Blair’s two machines had made 30 or 40 tests apiece, 
while Orton’s machine was new. 

Omitting all needless details, Table I gives a condensed 
summary of the results of this series. The same data are shown 
graphically in Fig. 1. 

The discussion of the results of Series F will be deferred until 
the data of Series G have been presented. Owing to failure to 
cooperate closely enough, the two laboratories were in a different 
stage of forwardness at the end of Series F, and Series G was 
tested and available for study at the same time that the Series F 
data were first exchanged. Up to this point, each laboratory had 
followed the prearranged schedule according to its own interpre¬ 
tation, and both Series F and G show similar differences in results 
due to this fact. 


Series G. 

The second material to be distributed jointly between the two 
laboratories was that predesignated as G. It consisted of 2,100 
bricks representing upper, middle and lower sections of the kilns. 
The only differences between the conditions of the test in Series G 
and F were those due to the increased wear of the channel steel 
staves, which were warped and distorted by peening. 


780 


Blair and Orton on the Rattler Test 


Table I.— Summary of Rattler Tests upon Bricks of Series F. 


Position of 
Bricks in 
Kiln. 


Cubic Shot, 

10 Bricks per 
Charge. 

Spherical Shot, 

10 Bricks per 
Charge. 

No Shot, 

15 Bricks per 
Charge. 

Orton, 
10 tests. 

Blair, 

10 tests. 

Orton, 
10 tests. 

Blair, 

10 tests. 

Orton, 

5 tests. 

Blair, 

5 tests. 



f Average.. . 

16.68 

19.89 

19.93 

17.41 

22.68 

21.2 

Lower Bench.. 

• 

Maximum. 

18.80 

24.9 

22.22 

21.3 

23.26 

22.8 



Minimum.. 

14.67 

17.3 

17.74 

153 

22.19 

19.0 



f Average.. . 

16.10 

18.31 

19.47 

16.35 

20.51 

20.3 

Middle Bench 


Maximum . 

17.50 

20.2 

20.81 

17.9 

21 .93 

21.0 



. Minimum.. 

14.61 

17.3 

17.81 

14.5 

19.00 

19.1 



f Average.. . 

18.52 

19.35 

20.93 

17.83 

24.19 

21.4 

Upper Bench.. 

• 

Maximum . 

20.40 

20.6 

23.75 

20.5 

25.23 

22.8 


1 

Minimum.. 

16.66 

18.4 

18.28 

14.7 

22 .49 

20.2 


Conditions of the Tests. —1,800 revolutions at 30 per minute. 

Barrel, 28 ins. diameter by 20 ins. long. 

Staves, 6-in. steel channels. 

Cubic shot charge: 225 lbs. if-in. cubes, and 75 lbs. sf by 2f by 
4f-in. blocks. 

Spherical shot charge: 225 lbs. if-in. spheres, and 75 lbs. 3$4 n » 
spheres. 

Average 





i6.io ; 

1 8.31V-—- — 

19.47-- 

16.35.- 

18.52 1 -- 

19.35 —- 

20.93- 

1 7.83—-- 


Orion 


Blair 


Cube Testi 
Sphere Test 


Test Number 


Fig. i. —Curves of Series F (Partial), 










































































Blair and Orton on the Rattler Test. 781 

The results of Series G are summarized in Table II and 
plotted in Fig. 2. 


Table II.— Summary of Rattler Tests upon Bricks of Series G. 


Position of 
Bricks in 


Cubic Shot, 

10 Bricks per 
Charge. 

Spherical Shot, 

10 Bricks per 
Charge. 

No Shot, 

15 Bricks per 
Charge. 

Kiln. 


Orton, 
10 tests. 

Blair, 

10 tests. 

Orton, 
10 tests. 

Blair, 

10 tests. 

Orton, 

5 tests. 

Blair, 

5 tests. 

Lower Bench.. 

f Average.. . 

| Maximum. 
[Minimum.. 

16.94 

19.44 

1563 

17.68 

19.90 

17.00 

20.07 

21.69 

19.06 

15.42 

17.50 

13.70 

22.74 
23.93 
21.88 

21.60 
23.10 
21.00 

Middle Bench. 

f Average.. . 
j Maximum. 

[ Minimum.. 

17.80 

18.83 

16.60 

20.32 

24.70 

17.20 

22.07 
29 70 
19.71 

18.64 

23.20 

16.30 

23.69 

25.04 

22.05 

21.90 

24.30 

20.80 

Upper Bench.. 

f Average.. . 

| Maximum. 

[ Minimum.. 

17.90 

20.77 

16.72 

18.80 

19.40 

18.20 

21.94 

22.60 

21.20 

17.33 

18.90 

15.60 

24.33 
24.45 
24.19 

24.70 

25.30 

24.20 


Conditions of the Tests .—Same as in Table I, except those due to 
distortion of the staves by peening. 


Average 




16.99 - 

17.60 — — ' 

20.07 -- 

15.42 - 


17.80 

20.32 — — 

22.07 -•- 

18 . 64 -—- 


17.90 -= 

'l 

18.80 — — — 

/ ' 

21 . 94 —— 


1 7.33 -—- 


Sphere Test 


Fig. 2.—Curves of Series G (Partial) 





























































7S2 Blair and Orton on the Rattler Test. 


Discussion of the Evidence of Series F and G .—The following 
points may be noted: 

1. The operators do not check»each other in any particular 
in either series, in comparing cube charges against cube charges, 
or sphere charges against sphere charges. 

2. The concurrence in averages in those charges in which no 
shot is used is much better, though not as good as expected. 

3. Orton’s results show his cube tests averaging 3 per cent, 
lower than his sphere tests. 

4. Blair’s results show his cube tests averaging 2 per cent, 
higher than his sphere tests. 

The radical failure of the two laboratories to check each other, 
and the curious direct reversal of the relation between cubic shot 
and spherical shot in the two laboratories, caused a halt in the 
work until some cause could be ascertained. 

The operating conditions were carefully compared. The 
speed of Blair’s machine was often a little less than Orton’s, but not 
enough to cause apprehension at the time. The condition of the 
rattlers was then discussed. In both laboratories, the channel-iron 
staves were seriously warped by the peening of the inner surface 
under the millions of blows. This warpage was worse on Orton’s 
machine, as it did the work alone, while at Blair’s laboratory the 
work was divided between two machines. In Orton’s machine, the 
diameter had been reduced an inch by this warpage and the surface 
was rendered rough by the edges of the staves warping inwards, so 
that a better chance was offered for the shot to “ climb’ ’ in running, 
and thus fall farther when they went back. At the end of Series 
G, Orton’s machine had made 180 tests and Blair’s machines 
about 127 tests each. A divergence in conditions had thus 
developed. 

Orton now discovered for the first time that Blair was not 
using the shot which had been sent from Columbus, but was using 
the “Over” shot which he had had made while waiting for the 
Columbus shot to arrive. The divergence in conditions thus 
involved the shot charges as welbas the staves, and it was decided 
to make a fresh start. 

Meanwhile, some additional data had been obtained by 
Orton before the above serious situation had been fully disclosed. 
This work was upon Series A and E, which had been received 




Blair and Orton on the Rattler Test. 783 


while tests of Series F and G were in progress. This is summarized 
in Table Ills 


Table III. 

Partial ^Results of Series A, by Orton. 


Position in Kiln. 


Lower Bench 


Middle Bench 


Upper Bench 



Cubic Shot. 

Spherical Shot 

f Average (5 tests). 

20.76 

23.54 

< Maximum... 

22.05 

24.14 

[ Minimum. 

18.86 

22.58 

f Average (5 tests). 

18.97 

21.95 

| Maximum. 

20.42 

23.28 

[ Minimum. 

18.08 

20.92 

f Average (5 tests). 

19.99 

23.40 

1 Maximum. 

21.53 

25.17 

[ Minimum. 

18.36 

22.28 


Partial Results of Series E, by Orton. 


Lower Bench 


Middle Bench 


f Average (5 tests). 

20.15 

23.56 

4 Maximum. 

21.97 

24.63 

[ Minimum. 

19.19 

22.53 

f Average (5 tests). 

18.39 

21.06 

| Maximum. 

19.64 

22.16 

[ Minimum. 

17.03 

19.18 


These results merely still further confirm that, under the 
procedure and conditions prevailing in the Orton Laboratory, the 
sphere test gives results averaging 3 per cent, higher than the cube 
test. 


Series C. 

In order to obtain comparable conditions, one of Blair’s 
machines and Orton’s machine were stripped and simultaneously 
installed with a complete set of new 15.5-lb. medium-steel channel 
staves, the same as those originally furnished. Blair also rejected 
the Over shot and put in the Columbus shot charges, both cubic 
and spherical. A new sample, designated C, was divided between 
the two laboratories, giving 1,050 bricks from the upper, middle 
and lower benches, to each laboratory. The results of this com¬ 
parison are shown in Table IV and are plotted in Fig. 3. 

The concordance between the two laboratories is very much 
better than in any of the preceding work. Cube tests now check 
cube tests and spherical tests now check spherical tests, but the 




































784 Blair and Orton on the Rattler Test. 

Table IV. —Summary of Rattler Tests upon Bricks of Series C. 


Position of 
Bricks in 


Cubic Shot, 

10 Bricks per 
Charge. 

Spherical Shot, 

10 Bricks per 
Charge. 

No Shot, 

15 Bricks per * 
Charge. 

Kiln. 

• 

Orton, 
10 tests. 

Blair, 

10 tests. 

Orton, 

10 tests. 

Blair, 

10 tests. 

Orton, 

5 tests. 

Blair, 

5 tests. 

Lower Bench.. 

f Average.. . 
j Maximum. 

[ Minimum.. 

21.71 

22.96 

20.40 

22.44 

25.07 

21.76 

22.76 

23.81 

21.14 

23.40 

24.74 

22.02 

27-27 

27.76 

26.17 

24.62 

26.64 

20.89 

Middle Bench. 

f Average.. . 

< Maximum. 

[ Minimum.. 

23.67 

26.11 

21.01 

23 83 
24.42 
22.22 

22.79 

24.76 

20.71 

24.61 

26.22 

23.36 

27.45 
28.91 
26-29 

26 35 
27.93 
24.23 

Upper Bench.. 

f Average.. . 

Maximum. 

[ Minimum.. 

21.93* 

23.78 

20.72 

22•18f 
22.57 
21 .34 

22.25* 

23.10 

21.59 

24 22f 

25 05 
22.27 

25.74 
26.09 
25.54 

24.53 

24.93 

23.85 


* Seven tests. f Five tests. 


Conditions of the Test. —Same as in Table I, except that each machine 
was equipped with new staves on starting, and the shot charges were of 
the same make in both laboratories. The cubic shot, however, were not 
made by the same foundry as the spherical shot. 

Average 


21.71 - 

. 22.44 - 


22.71 


23.40 - 




23.67 


23 . 83 --- 

22.79 - 

I 

24.61 - 



Cube Test 
Sphere Test 


Fig. 3.—Curves of Series C (Partial) 






































































Blair and Orton on the Rattler Test. 785 

relationship between the cube test and the sphere test has changed. 
In Orton’s data, where the sphere test has heretofore given results 
3 per cent, higher than the cubes, we now find it giving but slightly 
higher losses; while Blair, who heretofore found cubes giving 
persistently higher losses, now reverses his findings and shows 
spheres running 1.25 per cent, on the average higher than cubes. 

When the investigation had reached this point, it was clear 
that the shot were in some way connected with our inability to check 
each other. Blair, therefore, sent these irons to Mr. L. A. Touza- 
lin, Assistant Chief Chemist of the Illinois Steel Company, South 
Chicago, Ill., and they were carefully analyzed. The results 
are given in Table V. 


Table V.— Analysis of Cast Iron Shot. 


Element. 

O’Brien 

Cubes. 

Over 

Loudenslager 

Spheres. 

Cubes. 

Spheres. 

Combined carbon. 

0.45 

1.46 

1.59 

2.76 

Graphitic carbon. 

3.02 

2.01 

1.92 

041 

Silicon. 

1.73 

1.63 

1.24 

0.96 

Sulphur. 

0.08 

0.18 

0.18 

0.15 

Phosphorus. 

0.68 

0.82 

0.84 

0.53 

Manganese. 

0.51 

0.28 

0.27 

0.27 

Scleroscope readings. 

50.1 

60.1 

68.7 

72.1 


The data proved most illuminating. It showed the O’Brien 
iron to be practically a gray foundry iron, and very soft. The 
two batches from Over were of medium hard iron, but not nearly 
as hard as the white Loudenslager iron. 

The relation between the hardness of the irons and their wear¬ 
ing power seems clearly indicated. Orton, in five series of tests, 
aggregating more than 100 comparisons, found spheres of hard 
white iron giving persistently higher losses than cubes of soft 
foundry iron. Blair, in two series of tests aggregating 60 com¬ 
parisons, found spheres of moderately hard iron giving persistently 
lower results than cubes of the same iron. Blair, in one series of 
25 comparisons, with hard spheres and soft cubes, checked Orton’s 
findings, though with reduced differences between the two methods. 

The foregoing evidence forced the conclusion that the com¬ 
position of the metal to be used in the abrasive shot was a mat¬ 
ter of critical importance—sufficient to completely overthrow any 

50 

























7 86 


Blair and Orton on the Rattler Test. 


probability of making good checks between independent operators, 
unless using identical shot charges. 

It was therefore concluded to abandon, at least temporarily, 
the scheme which had been originally planned, and take up a more 
critical investigation into the effects of different kinds of shot. 

In order to still further simplify the work, it was desirable to 
continue the investigation with but one shape of shot. Before 
deciding which shape to employ, the data thus far obtained were 
carefully compared. 

Cubic Shot vs. Spherical Shot. 

The spherical shot had proven themselves superior in the 
following respects: 

i. Ease of Maintenance .—The cubic shot loses corners and 
edges very rapidly. In the case of soft and medium foundry irons, 
the cubes have to be replaced at the rate of about 11 per charge, or 
30 to 60 every five tests. This means that the average life of a 
cube is only 20 to 25 charges. Further, the point of rejection is a 
matter of some variability, depending upon the judgment of the 
operator. It is too laborious to accurately weigh each cube after 
each test, and any visual test involves the judgment as aforesaid. 
Spheres wear uniformly over their whole surface, from the begin¬ 
ning, and their rate of wear is much smaller than with new cubes. 
Cubes tend to become spheres by the wear of the rattler. 

The relative rates of loss of iron with cubes and spheres of the 
same make are shown herewith:— 

Losses in Pounds in Periods of Five Tests. 

“Over” Spheres. 

1 -35 
2.50 

1.10 
o. 90 
1.30 
1.60 


Averages. 8.41 1.46 

This shows six times as much wear on the cubes as on the 
spheres. Much more data could be given corroborating the above. 


“Over” Cubes. 

9 * 2 5 
13.60 

7-*5 

7-5o 

7-85 

7-55 

6.00 








Blair and Orton on the Rattler Test. 


787 


2. Effectiveness .—Where spheres and cubes of the same metal 
are used, so that no factor of variation is introduced except that of 
shape of the shot, the spheres are found to give lower abrasion 
losses. Tables VI and VII illustrate this fact. 


Table VI. Orton’s Laboratory. 

” Loudenslager” Iron (Second Lot). 



Brick, Series D. 

Staves, Lined Channels. 


Cubes. 

Spheres. 


21.74 

20.25 


25.70 

21.50 


24.03 

22.05 


23-75 

19.24 


24-33 

22.96 


23.71 

22.06 


22.05 

21.08 


24.20 

21.49 


23 - 3 ° 

22.18 


22.27 

21.98 

Average.. . 

. 2 3 • 5 ° 

21.47 

Maximum. 

. 25.70 

22.96 

Minimum.. 

. 21.74 

19.24 


Table VII. —Blair’s Laboratory. 

“Over” Iron op Medium Hardness. 



Series F 

Series G 

Series H 


(Lower Bench). 

(Lower Bench). 

(Middle Bench). 


Cubes. 

Spheres. 

Cubes. 

Spheres. 

Cubes. 

Spheres. 


18.3 

21.0 

17.0 

15.4 

29.9 

29.0 


19.6 

17.6 

19.5 

16.3 

29.0 

28.9 


18.5 

18.3 

17.9 

15.2 

33.3 

27.9 


19.9 

15.3 

17.3 

17.0 

29.1 

25.1 


24.9 

21.3 

17.2 

17.5 

30.8 

26.3 


21.9 

15.7 

17.5 

15.0 




19 5 

17.1 

173 

14.6 


• • • • 


17.6 

16.0 

18.7 

13.7 




17 .3 

15.7 

19.9 

15.0 




21.4 

16.1 

14.5 

14.5 

• • . • 

• • • • 

Average. 

19.8 

17.4 

17.96 

15.39 

30.4 

27.4 

Maximum. 

24.9 

21.3 

19.9 

17.5 

33.3 

29.9 

Minimum. 

17.3 

15.3 

14.5 

13.7 

29.0 

25.1 


These illustrations are taken at random from a great mass of 
similar data, and show clearly that where the iron is the same the 
spheres give a consistently lower figure than the cubes, by about 
2 per cent. 



































788 Blair and Orton on the Rattler Test. 

3. Kind of Wear .—Examination of the bricks tested does not 
disclose any characteristic differences in the kind of wear. The 
spheres seem to disclose cavities lying close to the surface of the 
bricks, just as the cubes do. 

On the strength of the marked gain in economy of iron, and 
the slight difference in the rate of wear of the bricks, the spheres 
were selected as the basis of all future experiments. 

A plan for a careful comparison of the behavior of shot made 
from different hard irons, with a view to fixing a chemical specifica¬ 
tion which would insure material of uniform value for this purpose, 
was now formulated. While the necessary supplies were being 
secured other work was being carried forward. 

Introductory Work on Staves. 

The stave originally adopted for the joint test was a plain 
6-in. medium-steel channel, weighing 15.5 lbs. per linear foot. 
At the time that the first sets were replaced, as stated in reference 
to Series C, the peening action of the charge had warped each 
channel to a marked degree. It was evident that it would be 
impossible to successfully straighten them. And, as the warpage 
increased, the results of the test became more erratic and widely 
divergent, especially in Orton’s machine, which was in the worst 
condition. 

It will be recollected that at the beginning of Series C, both 
Orton’s and Blair’s machines were equipped with new channel 
steel staves of the original type. 

During the time when Series C was being run, Blair used one 
of his machines to experiment upon a new set of channel staves 
lined with f-in. medium-steel wear-plates fastened to the face of 
the channel with 3 rivets, countersunk and dressed smooth. The 
results of the experiment were so encouraging as to justify the 
equipment of Orton’s machine with a similar set of lined channel 
staves. 

With machines in both laboratories equipped with lined 
channel staves, Series A and E were now carried nearly to com¬ 
pletion. The shot used in both laboratories was Loudenslager’s 
hard, white-iron spheres (Lot 1) and O’Brien’s soft, gray-iron 
cubes. 





Blair and 


Orton on the Rattler Test. 



Table VIII gives 


the summarized data of these two series. 


Table VIII. —Summary of Rattler Tests, using Lined Staves. 

Bricks of Series A (in part). 


Position of 
Bricks in 
Kiln. 


Cubic Shot, 

Soft Gray Iron. 

Spherical Shot, 
Hard White Iron. 

No Shot, 

15 Bricks per 
Charge. 

Orton, 

5 tests. 

Blair. 

Orton, 

5 tests. 

Blair, 

10 tests. 

Orton, 

5 tests. 

Blair, 

5 tests. 


f Average.. . 

18.07 


20 97 

20.34 

25.12 

23.57 

Lower Bench.. 

j Maximum. 

18.57 


22.69 

22.05 

26.21 

25.67 


[ Minimum.. 

16.87 

_d 

20.08 

18.33 

22.98 

22.29 


f Average.. . 

16.65 

XI 

1812 

19.14 

23.25 

21 73 

Middle Bench. 

j Maximum. 

1871 

0 

1915 

20.11 

24.84 

22 . £0 


[ Minimum.. 

15.24 

c3 

c3 

17.22 

17.15 

21.58 

20. CO 


f Average.. . 

18.26 

T3 

O 

18 48 

19.84 

22 26 

21 .28 

Upper Bench.. 

| Maximum. 

20.68 

£ 

19 .28 

22 05 

23.55 

23.27 


[ Minimum.. 

16.20 


17-03 

17.42 

21.88 

20.27 


Bricks of Series E (in part). 


Lower Bench.. 

f Average.. . 
j Maximum. 

(_ Minimum.. 

1801 

18.73 

16.55 

17.71 

19.07 

1699 

1 

20.85 

22.70 

20.15 

18.23* 

19.66 

17.00 

25.72 
26 66 
24.78 

21.78 

22.66 

21.03 

Middle Bench. 

f Average.. . 
j Maximum. 

[ Minimum.. 

16.61 

17.36 

15.36 

15.63 

16.04 

15.21 

18.49 

19.31 

16.84 

17.25* 

18.23 

15.60 

23.15 

23.51 

22 .74 

20.87 

21.30 
20.44 

Upper Bench.. 

f Average.. . 
j Maximum. 

[ Minimum.. 

16.52 

17 .45 
15.33 

17.06 

17.77 

16.00 

17.26 

17.72 

16.11 

17.36* 
18.01 
16.80 

21.26 

22.65 

19.83 

21.35 
21.89 
20.32 


The salient points to be noted in Table VIII are as follows: 

1. Both operators agree fairly well on both cube vs. cubes, and 
sphere vs. spheres. 

2. As between cubes and spheres, the data merely serve as 
a check on Series C, since the newly planned shot were not yet 
available and the old spheres and cubes were still being used. 
The hard spheres were inflicting from 1.5 to 1.75 per cent, greater 
loss than the soft cubes, on the average, and the quality of the iron 

is thus again seen to overweigh the difference in the shape of 
the shot. 

Examining now the influence of the new lined staves and the 
old un-lined staves, the comparison in Table IX can be compiled 
from Orton’s data. It is shown graphically in Fig. 4. 


* Average of 5 tests, instead of 10 as in column above. 
















































79 ° 


Blair and Orton on the Rattler Test 


Table IX.— Tests with Lined and Un-Lined Staves. 


Comparisons on Five Tests Each. 

Series A. 


Position of Bricks 
in Kiln. 


Old Staves.' 

(Badly warped and rough.) 

New Staves, Lined. 
(Smooth.) 

Lower Bench. 

Middle Bench. 

Upper Bench. 

f Cubes. 

20.76 

23.54 

1897 

21.95 

19.99 

23.40 

18.07 

20.97 

16.65 

18.12 

18.26 

18.48 

\ Spheres. 

f Cubes. 

1 Spheres. 

f Cubes. 

1 Spheres. 



Series E. 


Lower Bench 


Middle Bench. 



f Cubes. 

20.15 

18.01 


\ Spheres. 

23.56 

20.85 


f Cubes. 

18.39 

16.61 

* • • • 

\ Spheres. 

21.06 

18.49 


Using Cubic Shot (O'Brien) 



Average 


i 


19.90 - . 

1 7 65 — — — 


22.96 — 
19 12 -- 


Old Distorted Staves ■ —.— . Test Number 

i'New Smooth-Lined Staves “ — — 


Fig. 4. —Influence of Condition of Staves on Rattler Losses. 
Series A (Orton’s Results). 


The rough interior of the barrel, affording better opportunity 
for the shot to climb, and thus fall farther, and also for bricks to 
strike against rough edges of staves, is thus seen to occasion an 
increased loss of 2.8 per cent, on the average. 



































































Blair and Orton on the Rattler Test. 791 

At the end of this work the lined stave was still in excellent 
condition and presented only very slight convexities between 
rivets, due to peening. 

The Chicago or “No Shot” Test. 

The data obtained by this process have been shown in their 
place in all of the tables thus far, but little attention has been 
given to them in the discussions. At this point the evidence was 
reviewed, to decide whether or not to continue this test. 

For convenience, the averages of the “Chicago tests” of each 
series are assembled in Table X. 


Table X.— “Chicago Test” Comparisons. 


Series F. 


Bench. 

Orton. 

Blair. 

Remarks. 

Averages 
of 5 tests. 

General 
Average 
(15 tests). 

Averages 
of 5 tests. 

General 
Average 
(15 tests). 

Lower.... 
Middle.... 
Upper.... 

22.68 

20.51 

24.19 

22 46 

21.20 . 
22.80 

19 .00 

21.0 

Staves warped; interior of 
barrel rough. 

Series G. 

Lower.... 
Middle.... 
Upper.... 

22.74 

23.69 

24.33 

23.58 

21.60 

21.90 

24.70 

22.73 

Staves very badly warped; 
interior of barrel very rough. 


Series C. 


Lower.... 

27.27 


24.62 


Middle.... 

27.45 

26 82 

26 35 

25.16 

Upper.... 

25.74 


24.53 



Staves new; 
barrel smooth. 


interior of 


Series A. 


Lower.... 
Middle.... 
Upper.... 

25.12 

23 25 

22.66 

23.67 

23.57 

21.73 

21.28 

22.19 

Staves lined; interior of 
barrel smooth. 

Series E. 

Lower.... 
Middle.... 
Upper.... 

25.72 

2315 

21 .2u 

23 37 

21 .78 
20.87 
21.35 

21 .33 

Staves lined; interior of 
barrel smooth. 



















































79 2 Blair and Orton on the Rattler Test. 

The foregoing data show the following points: 

1. The results in Blair’s laboratory average 1.25 per cent, 
lower than in Orton’s. The same fact can be found in the shot 
tests up to this point, and later in this report in the tentative 
standard series. The explanation arrived at is a difference of 
speed, being below the proper limit in Blair’s machine. This 
difference was slight in the beginning, but became more important 
as the tests progressed, as shown later. 

2. The tests run higher in actual losses than in the correspond¬ 
ing shot tests. Selecting for comparison the tests executed with 
Loudenslager spherical shot (first lot) we have the values shown in 
Table XI. 


Table XI. —Comparison Between General Results of No Shot 

and Spherical Shot Tests. 


Series. 

No Shot. 

Spherical Shot. 

Orton’s Averages. 

Blair’s Averages. 

Orton’s Averages. 

Blair’s Averages. 

F. 

G. 

22.46 

23.58 

26.82 

21.00 

22.73 

25.16 

20.51 

21.16 

22.64 


C. 

23.89 

A. 

23 67 

22.19 

19.19 

19.80 

E. 

23.37 

21.33 

18.87 

17-61 


These figures are in nearly all cases the average of 15 charges 
each. The early sphere tests by Orton on Series A and E were 
excluded from the comparison on account of condition of staves. 
The sphere-test averages given for Series A and E are from the tests 
made when the staves had been lined. The corresponding all¬ 
brick charges were run at the same time and hence are comparable. 
The table shows a difference between the two methods amounting 
to about 3J per cent, on the averages. 

3. The same characteristic tendencies are shown in the various 
materials when tested by either of the two methods. Fig. 5 is a 
plot of the data given in Table XI. 

From the foregoing, it may well be questioned why the shot 
test should not be abandoned and the simpler and cheaper all¬ 
brick test be revived. 

So far as the evidence we have secured in this work is con¬ 
cerned, there is no reason why such a change might not be made. 

























Blair and Orton on the Rattler Test. 


793 


But, at the time that the old all-brick test was abandoned in favor 
of the shot test, it was demonstrated by Talbot and others that the 
shot charges had superior selective wear, where hard and soft bricks 
occurred in the same charge. In those days, when material was 
not as uniformly hard as it is at present, the importance of con¬ 
tinually watching for soft bricks was keenly felt, and it is not at 
all sure that this necessity does not still exist in many localities. 

For this reason it was thought best not to recommend the 
change from the shot test, unless a more searching inquiry is made 
to demonstrate fully the relative selective capacity of the two 
methods. The present work, while interesting, was always per- 



Senes F Senes G Series C - Series A Series E 

Fig. 5. —Comparison between Average Abrasion Losses of Charges 
without Shot and with Spherical Shot (Orton’s Results). 

formed on hard brick of rather uniform quality, and hence does not 
afford a good chance to study the whole problem. 

The Relative Performance of Spherical Shot Charges 
Made from Different Varieties of Hard Iron. 

Three manufacturers, all represented to be able to furnish a 
homogeneous and uniform grade of very hard white iron, were 
employed to prepare batches of spherical shot of the two sizes. 
Each manufacturer was to furnish two separate batches, separating 
the first order from the second by a time interval of several weeks, 
in order to see whether the quality furnished by the same plant in 
consecutive shipments would vary much. There was great delay 
in getting these various lots and dividing them between the two 
laboratories, and of one variety of shot but one batch was ever 
secured. 












794 


Blair and Orton on the Rattler Test. 


With these various lots of hard-iron spherical shot, a series of 
tests was made upon a new lot of bricks, Series D. A shipment of 
3,000 of this brand was obtained and divided equally between the 
laboratories. The shipment was a commercial one, and not 
selected for testing purposes as the previous lots had been. It 
therefore showed a somewhat greater variation within itself than 
some of the others. 

Table XII gives the data obtained in making this shot com¬ 
parison. 

The Loudenslager Shot .—The physical character of this shot 
was poor. While fairly accurate in weight, they were very 
frequently full of blow-holes or dimpled with sink-holes, due to 
contraction in cooling. They were brittle, easily crushed with a 
heavy hammer, and occasionally broke in the rattler. 

The analyses of the two lots of the Loudenslager shot are as 
follows: 



Lot 1. 

Lot 2. 

Combined Carbon.. 


1.48 per cent. 

Graphitic Carbon .. . 


1.47 “ 

Silicon. 


1.66 “ 

Manganese. 

..0.27 “ 

0.18 “ " 

Phosphorus. 

•• 0-53 “ 

0.72 “ 

Sulphur. 

..0.15 

0.20 “ 


The average results (io tests each) given by these two lots of 
shot, all other things being equal, were: 

Lot i. Lot 2. 


Orton . 23.37 21.47 

Blair . 21.86 20.15 


The second lot of shot varied widely in character from the 
first and gave distinctly lower wearing power in the rattler. The 
maximum and minimum figures are also lower in the second series, 
showing that it is not accidental. The lower results obtained with 
the second lot are exactly in line with the facts disclosed in Series 
F and G, where the Loudenslager shot (first lot) was compared 
with the Over shot from Indianapolis, whose composition was 
very similar to that of the second lot of Loudenslager shot. 

The wide divergence in chemical composition in the Louden¬ 
slager material was deemed by us a sufficient reason for giving it 
no further consideration as a possible future standard material, 



















Blair and Orton on the Rattler Test 


795 


Table XII. —Comparison of Work of Different Spherical Shots of 

Hard Irons. 


H. Loudenslager Foundry Company, Columbus, O. 



Lot 1. 

Lot 2. 


Orton. 

Blair. 

Orton. 

Blair. 


21 .OG 

21.25 

20.25 

17.94 


23. OG 

22.68 

21.50 

20.34 


20.96 

20.91 

22.05 

18.70 


24.31 

23.17 

19 .24 

20.41 


23.63 

22.95 

22 96 

20.14 


24.60 

20.71 

22.06 

20.64 


23.37 

21.14 

21.08 

20.49 


22.68 

22.85 

21.49 

23.37 


26.41 

21.87 

22.18 

19.03 


23.63 

21.16 

21.98 

20.50 

Average.. . 

23.37 

21.86 

21.47 

20.15 

Maximum. 

26.41 

23.17 

22.96 

23.37 

Minimum.. 

20.96 

20.71 

19.24 

17.94 


National Malleable Castings Company, Indianapolis, Ind. 



21.78 

20.50 

24.25 

21.39 


22.71 

21.86 

23.24 

20.91 


21.47 

20 .61 

21.78 

22.57 

* 

22.36 

21.75 

23.20 

21 .76 


21.31 

20.86 

24.40 

21.20 


21.91 

21 .69 

23.44 

20.52 


20.95 

21.99 

24.29 

21.22 


21.88 

20.25 

24.72 

23.47 


20.79 

2108 

22.12 

22.14 


19.57 

20.27 

24.60 

20.31 

Average.. . 

21.47 

21.08 

23.60 

21.54 

Maximum. 

22.71 

21.99 

24.72 

23.47 

Minimum.. 

19.56 

20.25 

21.78 

20.31 


American Car and Foundry Company, St. Louis, Mo. 



21.47 

19.68 



21.70 

21.41 



22.58 

19 .45 



21.94 

19.11 



24.43 

20.85 



21 .47 

18.43 



24.00 

19.90 



21 .80 

21.04 

Not furnished. 


22.61 

24.07 

20.53 


Average.. . 

22.60 

20.04 


Maximum. 

24.43 

21.41 


Minimum.. 

21.47 

18.43 















































796 


Blair and Orton on the Rattler Test. 


We had believed that its process of manufacture and the quality of 
materials would automatically, or by the self-interest of the maker, 
operate to keep its constitution and hardness about uniform, but 
the above demonstrates that this view was incorrect. 

The A merican Car and Foundry Company Shot. —The physical 
character of this shot was a little better than the preceding, but not 
much. It was roughly cast and had some blow-holes, but was 
tough. None of it broke in the rattler. It cost more than twice 
as much as the preceding, but with little real gain in quality. Its 
uniformity is unknown, as no second batch was secured. 

The analysis, and that of Loudenslager No. i for comparison, 
are given below. 

American Car and Loudenslager. 

Foundry Company. (Lot i.) 


Combined carbon ... 2.72 per cent. 2.76 per cent. 


Graphitic carbon. . 

0.89 “ 

0.41 “ 

Silicon. 

0 • 53 “ 

0.96 “ 

Manganese. 

0.31 “ 

0.27 “ “ 

Phosphorus. 

0.109 “ 

o -53 “ 

Sulphur. 

0.179“ 

0.15 “ “ 


The average results (10 tests each) given by these two lots of 
shot, were: 

American Car and Loudenslager. 

Foundry Company. (Lot 1.) 


Orton. 22.60 23.37 

Blair. 20.04 21.86 


The influence of the increased proportion of graphite in the 
American Car and Foundry Company shot is apparent, even where 
the combined carbon is so closely similar. 

The National Malleable Castings Company Shot. —The phys¬ 
ical character of this material was excellent. It was beauti¬ 
fully smooth and regular, free from blow-holes, very tough, and 
absolutely unbreakable with a sledge. The chemical composition 
of every heat from which spheres were cast was obtained from 
the heat-book of the company and was exceedingly regular. The 
metal was not a cupola-melted cast iron. It was melted in an 
air-furnace, and held there, subject to chemical influences which 
gradually converted its carbon wholly into the combined con¬ 
dition, It was tapped out and cast only when test showed it to be 














Blair and Orton on the Rattler Test. 


797 


converted to this new condition. It was not, therefore, properly 
comparable with an ordinary cast iron shot, though obtainable at 
about the same price. Table XIII gives the analyses of the two 
lots. 


Table XIII. 



Lot 1 . 

• 

Lot 2. 


Average 
of 22 
Analyses. 

Maximum. 

Minimum. 

Average 
of 10 
Analyses. 

Maximum. 

Minimum. 

Combined carbon 

2.74 

2.96 

2.51 

2.88 

3.21 

2.75 

Graphitic carbon 


. • • • 


• • . • 

• • • • 

• • • • 

Silicon. 

0.82 

1.00 

0.70 

0.78 

0.92 

0.67 

Manganese. 

0.26 

0.30 

0.19 

0.23 

0.26 

020 

Phosphorus. 

0.17 

0.18 

0.15 

0.19 

0.25 

0.15 

Sulphur. 

0.051 

0.07 

0.03 

0.05 

0.05 

0.04 


The results of the rattler test (average of io tests each) con¬ 
ducted with this shot are: 

Lot i. Lot 2. 


Orton. 21.47 23.60 

Blair. 21.08 21.54 


The remarkable uniformity of the above material and its 
physical perfection constitute a strong endorsement for the use of 
shot produced by this process of manufacture. 

Influence of Combined vs. Graphitic Carbon .—A study of the 
above data seems to point to the conclusion that the graphite is 
associated with the diversified wearing power of different irons. 
The data of Table XIV lend color to this view. 


Table XIV. 


Combined 

Carbon. 

Graphitic 

Carbon. 

Averages of 10 Tests Each. 

Orton. 

Blair. 

2.88 

trace 

23.60 

2154 

2.74 

trace 

21.54 

21.08 

2.76 

0.41 

23.37 

21.86 

2.72 

089 

22.60 

20.04 

1.48 

1 47 

21.47 

20.15 


A similar effect can also be observed in comparing graphitic 
cast-iron staves and hard white-iron staves. The effect of the 




































798 Blair and Orton on the Rattler Test. 

graphite probably is that of slight lubrication, promoting flow and 
decreasing opportunity for “climbing” of the shot, which reduces 
impact. A small piece of soap introduced into a rattler exercises 
a very pronounced similar effect. 

For the above reasons, it is believed that the air-furnace iron, 
devoid of all but traces of graphitic carbon, offers far the greatest 
chance of uniformity of any kind of iron attainable. 

Influence of Silicon .—Silicon is known to strongly affect the 
brittleness of cast iron. It does not affect the hardness of the 
metal itself, at least not within the limits considered in the present 
connection. Cast iron high in silicon would be more likely to 
crush in the rattler. Air-furnace iron is more likely to be low in 
this substance than cupola-melted iron. 

Manganese .—Manganese lends toughness, if the quantity be 
high, but it is not feasible to secure cast iron high in manganese 
except by making it to order and at great cost. 

Phosphorus and Sulphur .—Phosphorus makes “cold short” 
or brittle cast iron. Sulphur makes “hot short” steel—its effect 
on cast iron is probably in the direction of brittleness. 

Table XV gives a comparison of the relative behavior of the 
iron constituents of the charges mentioned above. 


Table XV.—Losses in Weight (in Pounds) of Charges of Iron 
Spheres; (300 lbs.) in Periods of Five Rattlings Each. 


Period. 

Loudenslager Spheres. 

National Malleable 
Casting Company’s 
Spheres. 

Lot 1. 

Lot 2. 

Lot 1. 

1 

2.06 

1.57 

0.87 

2 

3.00 

2.45 

0.37 

3 

1.75 

1.76 

0.57 

4 

1.25 

• • • • 

0.62 

5 

1.75 

• • • • 

0.63 

6 

• • • • 

• • • • 

0.56 

7 

• • • • 

• • • • 

0.93 

Averages. 

1.96 

1.93 

0.65 


The greater brittleness of the Loudenslager material, due to 
its higher silicon phosphorus and sulphur, is strongly shown in the 
relative losses in weight of iron. Many crushed and broken 
Loudenslager spheres were found in the rattler and removed from 



















Blair and Orton on the Rattler Test. 


799 


time to time, but never one of the National Malleable Company’s 
make. The presence of 0.41 per cent, of graphite in the former is 
not able to offset the effect of the above-mentioned ingredients. 

The Relative Performance of Different Types of Staves. 

The work on Series A and E showed clearly that the lined 
channel stave was a very great improvement over the plain one. 
Because of its compound structure, it was thought proper to 
subject it to a searching comparison with other types of simple, 
single-piece staves, before deciding on its adoption. 

There had been some researches made at Chicago and Cleve¬ 
land on the stave question, and although these results were unpub¬ 
lished we were informed that they indicated that differences in the 
thickness, rigidity and hardness of the staves influenced the results 
very markedly. Hence, it was decided to procure a series of dif¬ 
ferent staves and test them out in a competitive way, by running 
ten tests in each laboratory as follows:— 

1. Lined channel staves, as described. 

2. Steel plates, J in. thick. 

3. Steel plates, § in. thick. 

4. Steel plates, J in. thick. 

5. Manganese steel plates, J in. thick. 

6. Soft cast iron plates, J in. thick. 

7. Hard white cast iron plates, f in. thick. 

The manganese steel staves and both hard and soft cast iron staves 
were made from the same drawing, but different patterns were 
prepared in each case. In making these stave tests the Louden- 
slager spheres (Lot 1) were used exclusively by both operators. 
The comparison was run upon Series D material, the same as that 
used for the shot tests just discussed. Table XVI gives the data 
obtained. 

Analysis of the Data of the Stave Test .—The theory upon 
which the stave investigation was begun was that the rigidity or 
springiness of the stave was a matter of profound concern. This 
idea has been somewhat urgently advocated as the result of tests 
made in Chicago a year or two ago. Studying the results of our 
series, the data in Table XVII may be marshalled. 




Table XVI. —Showing Relative Performance of Different Types of Staves. 


800 Blair and Orton on the Rattler Test. 


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Blair and Orton on the Rattler Test. 


801 


Table XVII. 


Variety of Stave. 

Orton’s 

Results, 

10 tests. 

Blair’s 

Results, 

10 tests. 

Combined 
Results, 
20 tests. 

1-in. steel plate (medium soft). 

1-in. " ..). 

3-in..). 

15.5-lb. 6-in., medium steel channel, lined with f-in. 

medium steel wear plates.. 

3-in. cast slaves (manganese steel, intensely hard and 
rip'id ^... 

22.59 
f 21.971 

1 21.36/ 
22.49 

23.37 

21.12 

19.96 

20.65 

23.50 

21.60 

20.79 

21.86 

20.79 

19.56 

23.04 

21.78 

21.64 

22.61 

20.95 

19.76 

J-in. cast slaves (soft machinery iron). 

f-in. “ “ (hard white iron). 


1. Comparison of the data for the first four staves, all of 
which are made of medium steel, and which are arranged in order 
of rigidity, does not lend strength to the foregoing view. The 
fluctuations seem erratic and not greater than the variability of the 
material tested might easily explain. 

2. A second idea in the stave test was that hard surfaces 
would react upon an impinging brick differently from a soft or 
slippery graphitic surface. The known superiority of the special 
steels made for abrasion and grinding machinery, led us to try the 
use of a manganese steel stave. This material is not only intensely 
hard, but also very tough and may be bent considerably before 
breaking. The comparison of the data in the last four sets of 
staves—soft steel, hard steel, soft cast-iron, hard cast-iron—shows: 

(a) That the hard staves, both cast-steel and cast-iron, show 
less losses than the soft-steel staves. 

(b) That the soft cast-iron stave shows smaller losses than any 
other kind of stave. 

These data, while not conclusive, or indicating that the 
material of which the staves are made is of vital importance, do 
still seem to show that the metal of which the stave is made has 
some slight effect on the results. It was considered to be sufficient 
to justify the exclusion of a choice of stave material and warrant 
the specification of one material only as the standard equipment. 

3. The third point developed by this study is that the form, 
or the ability to retain its original form, is more important than 
anything else. The early tests of Series F, G, A, and E, all 
showed conclusively that as the staves became distorted by peening, 
they created a rough interior to the barrel and thus changed the 


51 


























8 o2 Blair and Orton on the Rattler Test. 

conditions, and made the results more erratic, and increased the 
actual rate of wear by 2 per cent, or more. This is very clearly 
shown in Table IX. 

I he data show that while the thin (and therefore springy) 
steel-plate staves are not inherently worse than others when new, 
they are not to be recommended because they peen rapidly and 
become distorted so soon. If used at all, they would require very 
frequent straightening, which is costly and likely to be neglected. 

The recommendation in favor of the channel steel stave is 
its superior rigidity compared to a flat steel plate. But the work 
of Series F and G and parts of Series A and E show clearly that 
it is still too easily distorted to be a good investment, and also, 
when distorted, it is practically out of the question to straighten 
it again, while a flat plate can be straightened by any blacksmith. 

The use of a face-plate to take up the peening and wear, and 
permit the channel stave to furnish the permanent support for it, 
has proved a very satisfactory step. The distortion of the unlined 
channel staves was so bad after 150 tests that they were continually 
stripping off heads of bolts, or tearing out bolt holes. Five boxes 
of bolts were used in repairs on one machine in about 200 tests. 
The lined channel stave completely avoids this difficulty since it 
remains rigidly in position; its bolts seldom work loose and never 
pull in two, or strip. The wear plate, on the other hand, being 
riveted firmly in its place at three points on its center line, and 
free to expand in most all directions under the peening action of 
the shot, is under no great stress, and while it will occasionally 
work loose and require re-riveting, this repair can be done easily 
and quickly by any ordinary mechanic or testing-machine operator. 
The peening action causes the wear plate to buckle up between 
rivets, presenting a slightly convex surface and fitting down tightly 
on the channel around the edges of the plate. This convexity does 
not exceed J in. in height after 150 tests. The cost of relining 
the channel is not great and thus the staves can easily be kept in 
good condition. 

Resumption of the Original Comparisons. 

The completion of the foregoing work now brought us to a 
point where the original plan could be resumed: that is, to deter¬ 
mine what degree of concordance could be obtained between two 




Blair and Orton on the Rattler Test. 803 


Table XVIII. —Comparisons by the Revised Method of Testing. 



Series A. 
(Middle Bench 
Only.) 


Orton. 

Blair. 


18.78 

1922 


20.06 

18.96 


20.24 

18.29 


18.72 

1783 


19.47 

1965 


19.26 

1894 


18.96 

17 24 


19.89 

18.88 


20.38 

19.54 


20.12 

19.77 

Average. • • 

19.59 

18.83 

Maximum. 

20.38 

1977 

Minimum.. 

18.72 

17.24 


Series C. 

Series D. 

Orton. 

Blair. 

Orton. 

Blair. 

23-80 

23.78 

21.78 

20.50 

24 • 44 

23 82 

22.71 

21.86 

23-95 

24.11 

21.47 

20.61 

24.97 

23.84 

22.36 

21 75 

24.49 

23 09 

21 .31 

20.86 



21 91 

21.69 



20 95 

21 99 

. 


21.88 

20.25 

..... 


20.79 

21 .08 



19.56 

20.27 

24.33 

23.72 

21.47 

21.08 

24.49 

24.11 

22 71 

21.99 

23 80 

23.09 

19.56 

20.25 


Series E. 

(6 from Middle 
Bench and 4 
from Lower 
Bench.) 

Series F. 

(4 Top, 

3 Middle, 

3 Lower.) 

Orton. 

Blair. 

Orton. 

Blair. 

18.55 

18.23 

20.09 

18.08 

19.02 

18.83 

19.60 

20.54 

20.87 

19.37 

1808 
19 89 
16.81 
1789 
18.20 
19.03 
17.82 
15.69 
1682 
17.84 

17-51 
1844 
18.75 
18.63 
17.99 
17 30 
17.48 
19.51 
18.70 
17.74 

16.16 

16.06 

15.42 

17.25 

16-80 

19.72 

17.49 

15.38 

17.86 

14.44 

19.31 

17.80 

18.20 

1695 

20 87 
18.08 

19.89 

15.69 

19.51 

17.30 

19.72 

14.44 



Series G. 

(4 Top and 

6 Middle.) 

Series H. 

(All Middle 
Bench.) 


Orton. 

Blair. 

Orton. 

Blair. 


1914 

17.90 

18.45 

18.24 

18.60 

19.38 

18.53 

19.35 

1913 

18.81 

1635 

15.50 

17.68 

17.27 

17.35 

1654 

1711 

16.22 

16.37 

17.58 

25.67 
30.47 
30 .23 
25.66 
29.76 

23.33 
25.07 

28.34 
29.44 
30.25 

27.20 

25.59 
28.87 
24.41 
26.03 
27 .76 

24.59 
25 07 
27 .26 
25 65 

Average. • ■ 

18.77 

17.39 

27.82 

26.24 

Maximum. 
Minimum.. 

1958 

17.90 

17.68 

15.50 

30.47 

23.33 

27.76 

24.41 


Series K. 

Series 

M. 


Series P. 

Orton. 

Blair. 

Orton. 

Blair. 

Orton. 

Blair. 

20 

30 

16 

40 

18 

41 

21. 

03 

16 

40 

15 

34 

18 

42 

17. 

42 

18 

08 

17. 

59 

16 

46 

16 

43 

17 

68 

17 

41 

20 

36 

19 

26 

16 

81 

16 

95 

19 

42 

16 

49 

18 

40 

18 

62 

17 

40 

17 

70 

18 

.97 

18 

54 

18 

.78 

17 

97 

16 

84 



17 

59 

17 

56 

19 

64 

21 

99 


. # 



20 

.23 

17 

20 

17 

24 

16 

94 


# # 



18 

.57 

18 

04 

19 

25 

19 

67 


# , 



18 

.46 

18 

23 

18 

38 

17 

91 





19 

.63 

18 

37 

20 

20 

21 

65 





18 

92 

17 

56 

19 

07 

19 

25 

16 

.78 

♦ 

16 

60 

20 

.30 

18 

54 

20 

.37 

21 

65 

17 

40 

17 

70 

17 

.59 

16 

40 

17 

24 

16 

94 

16 

40 

15 

34 


operators when testing the same brick and following the same 
specifications. Irregularities due to variation in the quality of the 
shot and the kind and condition of the staves, which had not 
previously been known, could now be provided for. The other 
variable factors in the rattler test, such as rate of rotation, duration 
of rotation, number of bricks per charge, etc., having been covered 
in the old specifications and in use for ten years, had been rather 
well determined, and no developments in this investigation had 
given any reasons to suggest their overthrow. 
































































































004 Blair and Orton on the Rattler Test. 

For the new comparisons, the following plan was made: 
First: To secure twenty charges of ten bricks each from ten 
different manufacturers of paving bricks—a total of 200 charges. 

Second: These were to be divided equally between the two 
laboratories to be tested by the new plan. 

Third: The samples to be selected were to be taken as far as 



Average 


* 

19 . 59 —*-— 
18 . 03 — — — 


c 

0) 

o 

L. 

0 ) 

CL 


in 

<n 

o 


Q) 


co 

cc 



21.47 - 

21 . 08 —— — 


19.31 - 

17 . 80 -- 


Orton's Results - Test Number. 

Blair's Results- 

Fig. 6 .—Degree of Concurrence attained with Improved Spherical Shot 

and Lined Steel Staves. 


possible from the remainder of the large car-load samples used in 
Series A, C, D, E, F and G. The other four samples were to be 
secured direct from the manufacturers and were to represent 
what they considered to be first-class material—perhaps not 
their best, but certainly well above the average in uniformity 
and exterior excellence. Of the six samples taken from the old 
series, there were not enough bricks available from a single 
bench of the kiln to make the requisite 20 charges of each brand. 














































Blair and Orton on the Rattler Test. 



In this case, charges were compounded from two or even three 
benches. When this was done, each charge was made to contain 
the same number of bricks from the several benches as every other 
charge in the same series, thus making the charges strictly com¬ 
parable. 

Fourth: The method of testing was as follows: 

(a) The shot charge should consist of ten 3f-in. spheres, 


20 


<15 


10 



\ 


— 

✓ 

/ 

/ 

/ 

/ 

/ 


Z 3 

s 

\ ^ 

s 

V 

\ 

Ser 

ies F <4 

bricks fron 

iTop, 3 fro 

m Middle, 

3 from Low 

ter Bench, 

_1 

in each ch< 

LJ 

•> 

irge) 


Average 


ta.20- 

1 6.93- 




Orton's Results ■" "— ~ Ofest Number 

Blair's Results — — 


Fig. 7.—Degree of Concurrence attained with Improved Spherical Shot 

and Lined Steel Staves. 


weighing as nearly as possible 75 lbs., and as many if-in. spheres 
made by the National Malleable Castings Company, the proper¬ 
ties of which have been discussed, as would bring the combined 
weight to 300 lbs. 

(b) The lined channel steel staves were to be used and relined 
whenever peened to a serious extent, and in no case to be run 
more than 150 tests without renewal. 
















































8o6 


Blair and Orton on the Rattler Test. 


(c) Other conditions were to remain the same as in the 
original procedure. 

The results of these comparisons are given in Table XVIII, 
and are plotted in Figs. 6, 7 and 8. 

The study of the foregoing shows that Orton’s averages are 
regularly higher than Blair’s. The amounts are not large: +0.76, 
0.61, 0.39, 1.51, 1.25, 1.36, 1.58, 1.36, 0.18, and one —0.18. The 



Orton's Results Test Number 

Blair's Results — 


p IG . g.—Degree of Concurrence attained with Improved Spherical Shot 

and Lined Steel Staves. 


average of these amounts is +0.88, Orton over Blair. If the sign 
of these differences was not practically one way they would be 
construed as satisfactory checks. But, since they point persistently 
in one direction, there must be a reason for it. 

Influence of Speed of Rotation .—The data of each observer was 
again searched and a difference in speed was found, which had been 
noted earlier in the joint work and which was trifling at that time, 




















































Blair and Orton on the Rattler Test. 


807 


Table XIX. —Comparison of Rattler Losses and Speed of 

Revolution. 



Orton. 

Blair. 


Rattler Losses. 

Average Speed, 

R. P. M. 

Rattler Losses. 

• 

Average Speed, 

R. P. M. 


18.55 

30.12 

18.08 

29.75 


18.23 

29.71 

19.89 

29 50 


20-09 

29.62 

16.81 

27.75 


18.08 

29.71 

17 89 

28.33 


19.02 

29.75 

18.20 

27.69 


18.83 

30.17 

19.03 

3010 


19.60 

30 04 

17 .82 

29.38 


20 54 

30 34 

15.69 

27.75 


20.87 

30.25 

16.82 

28.57 


19.37 

30.42 

17.84 

28.33 

Average.. . 

19.31 

30.01 

17.80 

28.71 


but which had now become much more considerable. Table XIX 
from Series E, which shows about the highest average discrepancy 
between Orton and Blair, was selected to illustrate this point. 

There would seem to be but little doubt that these low speeds 
on Blair’s machine during the winter months of 1910-11 were 
responsible in whole or in part for the persistently low results 
which he secured.- 

In order to obtain a final comparison, in a laboratory in which 
this speed factor could be corrected, arrangements were made for 
Blair to use a newly installed machine in the Laboratory of the 


Table XX. —Comparison, Series F (second), under Controlled 

Speed Conditions. 


Orton. 

Blair. 

Loss. 

R.P.M. 

Remarks. 

Loss. 

R.P.M. 

Remarks. 

17.25 

30.04 

Lining was near its 

15.78 

30.00 

Lining was new and 

16.94 

30.08 

point of rejection; viz., 

15.24 

29.84 

in good order; only 3 

19.27 

30.08 

128-133 tests. It was 

16.59 

29.75 

or 4 tests had been rua 

17.55 

30.04 

warped and peened con- 

19.13 

29.71 

on it. 

18.92 

30 04 

siderably. 

17.03 

29.71 


16.55 

30 .22 

New lining was in- 

18.56 

29 75 


15.86 

30.25 

stalled complete and 

16.20 

29.75 


15.44 

29.96 

these five tests run 

14.58 

29.99 


15.65 

29 75 

upon it without pre- 

16.04 

29.79 


18.45 

29.96 

liminary wear. 

14.59 

29.71 


17.19 

30.04 


16.37 

29.80 











































&o8 


Blair and Orton on the Rattler Test. 


Ohio State Highway Commission-. This machine was a duplicate 
of that used in the rest of this study. The bricks were 200 in 
number taken from a commercial shipment standing upon the 
street ready for laying. Each operator received 100 and made 10 
tests. The results are given in Table XX. 

The last five tests made by Orton in the above table, and the 
entire ten by Blair are about as closely comparable as can be 
obtained. The first five tests by Orton were made with the lining 
about ready for rejection, which may or may not have affected the 
results. 

There are too few data available to prove with certainty that 
low speed was the cause of Blair’s results running lower than 
Orton’s in the final ten comparisons, but this presumption has been 
somewhat strengthened by the above test. 


Conclusions. 

1. Spherical shot, of the quality used in the latter part of this 
study, have very great advantages over cubic or rectangular shot. 
The losses of weight of the shot themselves is reduced to a mere 
trifle, the condition of the charge changes very slowly, and is much 
cheaper to maintain. 

2. The lined steel channel stave has the advantage of any other 
kind known to the writers in that it can be kept in good order with 
the minimum expense or attention. The distortion due to peen- 
ing, which is shown by all staves, is here taken up by the wear- 
plate, which is inexpensive and easily renewed. 

3. The speed of rotation is believed to exert enough influence 
on the results to justify closer limits than were permitted under the 
old standards. It is believed to be one very fruitful cause of the 
difficulties experienced by operators in checking each other. 

4. There remain some other factors of the rattler test not 
covered in the old specifications, which have not as yet been 
investigated. Their influence may be found to be noticeable by 
careful study and it may be desirable to cover them by exact 
specification. Some of these points are (a) the method of support¬ 
ing the rotating barrel; and (b), the method of driving the barrel, 
whether by steam engine, gas engine or electric motor, or by 



Blair and Orton on the Rattler Test. 809 

direct, belt, rope, chain, or friction drive. In the opinion of the 
writers, no great importance attaches to these factors and some 
divergence of practice may continue in these respects without 
destroying the ability of different operators to check each other 
within the limits which the natural fluctuation of the material itself 
imposes. 

5. The use of a uniform data sheet for recording and reporting 
rattler tests is very important. It greatly assists in securing 
uniformity in doing the work. 

Recommendations. 

In view of the above conclusions we present the following 
revised specifications for the rattler test upon paving bricks, to 
take the place of the specifications of the National Brick Manu¬ 
facturers Association of 1901. 


REVISED SPECIFICATIONS FOR THE RATTLER TEST 

UPON PAVING BRICK. 

The Rattler 

The machine shall be of good mechanical construction, self-contained, 
and shall conform to the details of material and dimensions, as set forth 
in the following specifications. 

The Barrel. —The barrel of the machine shall be made up of the heads, 
headliners and staves. 

The heads shall be cast with trunions in one piece. The trunion 
bearings shall not be less than two and one-half (2^) inches in diameter 
or less than six (6) inches in length. 

The heads shall not be less than three-fourths (f) inch thick nor 
more than seven-eighths (J) inch. In outline they shall be a regular 
fourteen-sided (14) polygon inscribed in a circle twenty-eight and three- 
eighths (28D inches in diameter. The heads shall be provided with 
flanges not less than three-fourths (£) inch thick and extending outward 
two and one-half (2^) inches from the inside face of head to afford a means 
of fastening the staves. The flanges shall be slotted on the outer edge, so 
as to provide for two (2) three-fourths (£) inch bolts at each end of each 
stave, said slots to be thirteen-sixteenths (y|) inch wide and two and 
three-fourths (2I) inches center to center. Under each section of the 
flanges there shall be a brace three-eighths (f) inch thick and extending 
down the outside of the head not less than two (2) inches. Each slot shall 
be provided with recess for bolt head, which shall act to prevent the turn¬ 
ing of the same. There shall be for each head a cast iron headliner one (1) 



8 io 


Blair and Orton on the Rattler Test. 


inch in thickness and conforming to the outline of the head, but inscribed 
in a circle twenty-eight and one-eighth (28-J-) inches in diameter. This 
liner or wear plate shall be fastened to the head by seven (7) five-eighths 
(|) inch cap screws, through the head from the outside. These wear 
plates, whenever they become worn down one-half (£) inch below their 
initial surface level, at any point of their surface, must be replaced with 
new. The metal of which these wear plates are to be composed shall be 
what is known as hard machinery iron, and must contain not less than 
one (1) per cent, of combined carbon. The faces of the polygon must be 
smooth and give uniform bearing for the staves. To secure the desired 
uniform bearing, the faces of the head may be ground or machined. 

The Staves .—The staves shall be made of six (6) inch medium steel 
structural channels twenty-seven and one-fourth (27^) inches long, 
weighing fifteen and five-tenths (15.5) pounds per linear foot. 

The channels shall be drilled with holes thirteen-sixteenths (-|~|) 
inch in diameter, two (2) in each end, for bolts to fasten same to head, 
the center line of the holes being one (1) inch from either end and one and 
three-eighths (i|) inches either way from the longitudinal center line. 

The space between the staves will be determined by the accuracy of 
the heads, but must not exceed five-sixteenths (j^-) inch. The interior 
or flat side of each channel must be protected by a lining or wear plate 
three-eighths (§) inch thick by five and one-half (5^) inches wide by 
nineteen and three-fourths (19I) inches long. The wear plate shall consist 
of medium steel plate, and shall be riveted to the channel by three (3) 
one-half (%) inch rivets, one of which shall be on the center line both ways 
and the other two on the longitudinal center line and spaced seven (7) 
inches from the center each way. The rivet holes shall be countersunk 
cn the face of the wear plate and the rivets shall be driven hot and 
chipped off flush with the surface of the wear plate. These wear plates 
shall be inspected from time to time, and if found loose shall be at once 
reriveted, but no wear plate shall be replaced by a new one except as 
the -whole set is changed. No set of wear plates shall be used for more 
than one hundred (100) tests under any circumstances. The record 
must show the date when each set of wear plates goes into service and 
the number of tests made upon each set. 

The staves when bolted to the heads shall form a barrel twenty (20) 
inches long, inside measurement, between wear plates. The wear plates 
of the staves must be so placed as to drop between the wear plates of the 
heads. These staves shall be bolted tightly to the heads by four (4) 
three-fourths (£) inch bolts, and each bolt shall be provided with lock 
nuts, and shall be inspected at not less frequent intervals than every 
fifth (5th) test and all nuts kept tight. A record shall be made after each 
such inspection, showing in what condition the bolts were found. 

The Frame and Driving Mechanism .—The barrel should be mounted 
on a cast-iron frame of sufficient strength and rigidity to support same 
without undue vibration. It should rest on a rigid foundation and be 
fastened to same by bolts at not less than four (4) points. 




Blair and Orton on the Rattler Test. 


8ii 


It should be driven by gearing whose ratio of driver to driven should 
not be less than one (i) to four (4). The counter shaft upon which the 
driving pinion is mounted should not be less than one and fifteen-six¬ 
teenths (1 y-g-) inches in diameter, with bearings not less than six (6) 
inches in length and belt driven, and the pulley should not be less than 
eighteen (18) inches in diameter and six and one-half (6£) inches in face. 
A belt of six (6) inch double-strength leather, properly adjusted, so as to 
avoid unnecessary slipping, should be used. 

Abrasive Charge. 

(а) The abrasive charge shall consist of two sizes of cast-iron spheres. 
The larger size shall be three and seventy-five-hundredths (3.75) inches 
in diameter w r hen new and shall weigh when new approximately seven 
and five-tenths (7.5) pounds (3.40 kilos) each. Ten shall be used. 

These shall be weighed separately after each ten (10) tests, and if 
the weight of any large shot falls to seven (7) pounds (3.175 kilos) it shall 
be discarded and a new one substituted; provided, however, that all of 
the large shot shall not be discarded and substituted by new ones at any 
single time, and that so far as possible the large shot shall compose a 
graduated series in various stages of wear. 

The smaller size spheres shall be when new one and eight hundred 
seventy-five-thousandths (1.875) inches in diameter and shall weigh not 
to exceed ninety-five-hundredths (0.95) pounds (0.430 kilos) each. Of 
these spheres so many shall be used as wall bring the collective weight of 
the large and small spheres most nearly to three hundred (300) pounds, 
provided that no small sphere shall be retained in use after it has been 
worn down so that it will pass a circular hole one and seventy-five- 
hundredths (1.75) inches in diameter, drilled in a cast-iron plate one- 
fourth (£) inch in thickness or -weigh less than seventy-five-hundredths 
(0.75) pounds (0.34 kilos). Further, the small spheres shall be tested by 
passing them over such an iron plate drilled with such holes, or shall be 
weighed after every ten (10) tests, and any -which pass through or fall 
below specified weight, shall be replaced by new spheres, and provided, 
further, that all of the small spheres shall not be rejected and replaced by 
new ones at any one time, and that so far as possible the small spheres 
shall compose a graduated series in various stages of wear. At any time 
that any sphere is found to be broken or defective it shall at once be 
replaced. 

(б) The iron composing these spheres shall have a chemical composi¬ 
tion within the following limits: 


Combined carbon.Not less than 2.50 per cent. 

Graphitic carbon.Not more than 0.10 per cent. 

Silicon.Not more than 1 per cent. 

Manganese.Not more than 0.50 per cent. 

Phosphorus.Not more than 0.25 per cent. 

Sulphur. .Not more than 0.08 per cento. 
















8l2 


Blair and Orton on the Rattler Test. 


For each new batch of spheres used the chemical analysis must be 
furnished by the maker, or be obtained by the user, before introduction 
into the charge, and unless the analysis meets the above specifications, 
the batch of spheres shall be rejected. 

Brick Charge. 

The number of bricks per charge shall be ten (10) for all bricks of the 
so-called ‘ ‘ block size ” whose dimensions fall between from eight (8) to 
nine (9) inches in length, three (3) and three and three-fourths (3!) 
inches in breadth and three and three-fourths (3!) and four and one- 
fourth (4!) inches in thickness. No block should be selected for test 
that would be rejected by any other requirements of the specifications. 

The brick shall be clean and dried for at least three (3) hours in a 
temperature of one hundred (100) degrees Fahrenheit before testing. 

Speed and Duration of Revolution. 

The rattler shall be rotated at a uniform rate of not less than twenty- 
nine and one-half (29^) nor more than thirty and one-half (30^) revolu¬ 
tions per minute, and eighteen hundred (1,800) revolutions shall constitute 
the standard test. 

A counting machine shall be attached to the rattler for counting the 
revolutions. A margin of not to exceed ten (10) revolutions will be 
allowed for stopping. Only one (1) start and stop per test is regular and 
acceptable. 

Calculation of the Results. 

The loss shall be calculated in percentage of the original weight of 
the dried brick composing the charge. In weighing the rattled brick, 
any piece weighing less than one (1) pound shall be rejected. 

Records. 

(a) The operator shall keep an official book, in which the alternate 
pages are perforated for removal. The record shall be kept in duplicate, 
by use of a carbon paper between the first and second sheets, and when all 
entries are made and calculations are completed the original record shall 
be removed and the carbon duplicate preserved in the book. All calcula¬ 
tions must be made in the space left for that purpose in the record blank, 
and the actual figures must appear. The record must bear its serial num¬ 
ber and be filled out completely for each test, and all data as to dates 
of inspection and weighing of shot and replacement of worn-out parts 
must be carefully entered, so that the records remaining in the book 
constitute a continuous one. In event of further copies of a record being 
needed, they may be furnished on separate sheets, but in no case shall 
the original carbon copy be removed from the record book. 

(b) The blank form upon which the record of all official brick tests 

is to be kept and reported is: 




Blair and Orton on the Rattler Test. 


813 


REPORT OF 

STANDARD RATTLER TEST OF PAVING BRICK 

Identification Data Serial No. 

Name of the firm furnishing sample... 

Name of the firm manufacturing sample.... 

Street or job which sample represents.*. 

Brands or marks on the brick. 

Quantity furnished.Drying treatment. 

Date received.Date tested. 

Length.Breadth.Thickness.. 

Standardization Data 


Number of charges tested since last inspection 


Weight of Charge 
(After Standardization) 

Condition of Locknuts 
on Staves 

Condition of Scales 

10 Large spheres 



Small spheres 



Total 

# 



Number of charges tested since stave linings were renewed 
Repairs (Note any repairs affecting the condition of the barrel) 


Running Data 


Time Readings 

Revolution Counter 
Readings 

Running Notes* 
Stops, etc. 


Hours 

Minutes 

Seconds 



Beginning of test. 

Final Reading.... 





Weights and Calculations 


I 

! 

Initial Weight of 10 Bricks. .. ■, 

Final Weight of Same.• 

j 

Loss of Weight.| 

1 

I 

1 


Percentage Loss 
(Note. The Calculation Must Appear) 


Number of broken bricks and remarks on same. 

I certify that the foregoing test was made under the specifications of 

...and is a true record. 

(Signature of 
Tester) 


Date 


Location of Laboratory 
























































814 Blair and Orton on the Rattler Test. 

For the use and convenience of others, a drawing of a machine 
which meets the above specifications is furnished herewith. It is 
not a part of the specifications. It is important, however, in the 



opinion of the writers, that uniformity in apparatus and equipment 
shall prevail to the largest possible extent, as an aid in securing 
uniformity of results, and close adherence to the type of machine 
here presented is therefore greatly to be desired. 

























































































































































































































































































































LIBRARY OF CONGRESS 



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